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path: root/drivers/thermal/rockchip_thermal.c
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Diffstat (limited to 'drivers/thermal/rockchip_thermal.c')
-rw-r--r--drivers/thermal/rockchip_thermal.c36
1 files changed, 23 insertions, 13 deletions
diff --git a/drivers/thermal/rockchip_thermal.c b/drivers/thermal/rockchip_thermal.c
index 9c6ce548e363..3aa46ac7cdbc 100644
--- a/drivers/thermal/rockchip_thermal.c
+++ b/drivers/thermal/rockchip_thermal.c
@@ -193,19 +193,20 @@ static u32 rk_tsadcv2_temp_to_code(long temp)
static long rk_tsadcv2_code_to_temp(u32 code)
{
- int high, low, mid;
-
- low = 0;
- high = ARRAY_SIZE(v2_code_table) - 1;
- mid = (high + low) / 2;
-
- if (code > v2_code_table[low].code || code < v2_code_table[high].code)
- return 125000; /* No code available, return max temperature */
+ unsigned int low = 0;
+ unsigned int high = ARRAY_SIZE(v2_code_table) - 1;
+ unsigned int mid = (low + high) / 2;
+ unsigned int num;
+ unsigned long denom;
+
+ /* Invalid code, return -EAGAIN */
+ if (code > TSADCV2_DATA_MASK)
+ return -EAGAIN;
- while (low <= high) {
- if (code >= v2_code_table[mid].code && code <
- v2_code_table[mid - 1].code)
- return v2_code_table[mid].temp;
+ while (low <= high && mid) {
+ if (code >= v2_code_table[mid].code &&
+ code < v2_code_table[mid - 1].code)
+ break;
else if (code < v2_code_table[mid].code)
low = mid + 1;
else
@@ -213,7 +214,16 @@ static long rk_tsadcv2_code_to_temp(u32 code)
mid = (low + high) / 2;
}
- return 125000;
+ /*
+ * The 5C granularity provided by the table is too much. Let's
+ * assume that the relationship between sensor readings and
+ * temperature between 2 table entries is linear and interpolate
+ * to produce less granular result.
+ */
+ num = v2_code_table[mid].temp - v2_code_table[mid - 1].temp;
+ num *= v2_code_table[mid - 1].code - code;
+ denom = v2_code_table[mid - 1].code - v2_code_table[mid].code;
+ return v2_code_table[mid - 1].temp + (num / denom);
}
/**